Applicators of this type are also referred to as wire core applicators.
These applicators are still greatly appreciated today, because not only do they afford advantages with regard to their application, but also have various advantages in production that cannot be achieved with the injected applicators that compete with them. For example, small series can also be manufactured rather effectively because as a rule, very different wire core applicators can be produced on the existing production systems without considerable sums having to be invested in new tools for the one special applicator, unlike for injected applicators.
In general, it also applies to wire core applicator: that they are supposed to meet two requirements, in particular:
Their bristle covering is supposed to have as great a mass storage capacity as possible so that the applicator needs to be dipped into the cosmetics supply only once or only a few times in order to envelop the eyelashes with a sufficiently voluminous layer of mascara mass.
On the other hand, their bristle covering is supposed to have as good a separation capacity as possible, i.e. the capacity of separating obliquely overlying eyelashes of the curve of the eyelashes and aligning them in a largely parallel manner. The reason for this is not least that the eyelashes can only, be provided with the desired volume by means of the mascara mass if they are each coated all around individually, and not already previously drenched and stuck together in clumps with mascara mass.
In general, it thus applies to wire core applicators that they are supposed to meet high requirements, in particular, for the mass storage capacity with regard to the substance that is to be applied with them.
Various solutions have already been proposed in the prior art to take account for this.
For example, U.S. Pat. No. 4,733,425 proposes the use of bristles that are internally hollow or have a star-shaped, non-circular cross section. Such bristles have an excellent mass storage capacity but do not contribute to any significant improvement of the separation capacity of the applicator. In particular, this is due to the fact that these bristle cross sections result in bristles that, compared with cylindrical bristles made from solid material, are significantly more susceptible to buckling and therefore have a poorer capacity of penetrating between overlying eyelashes of the curve of the eyelashes. Because as soon as bristles of this type impact one or more eyelashes with their end faces, they tend to buckle instead of forcefully pushing the eyelashes aside and thus separating them.
In contrast, U.S. Pat. No. 5,161,555 proposes the use of heavily waved filaments in order to produce an improved wire core applicator, it is thus possible to obtain a very uniform bristle covering, just as according to the teaching of U.S. Pat. No. 5,161,554, which proposes the use of filaments with great diameter variations, i.e. filaments that, locally, have a very small diameter and, directly thereafter, in the immediate vicinity, a considerably larger diameter. Both of the latter patents, however, are unable to contribute substantially to the improvement of the separation capacity.
Only in passing, it may be noted that an applicator with injection-molded bristles is known from the U.S. Pat. No. 4,964,429, which is characterized in that the bristles are configured in a clearly conically shaped manner and are arranged with a not inconsiderable, defined distance from each other. Such bristles do indeed exhibit a good separation capacity. However, the bristle configuration recommended by this patent can only be realized in injection-molded applicators, not in wire core applicators. Therefore, this patent is also incapable of contributing to the improvement of wire core applicators.
In practice, wire core applicator with bristles whose tips are ground, so that they taper significantly, have already become known.
The use of such bristles results in a substantial improvement of the separation capacity in wire core applicators.
However, there is still a further need for optimization, particularly if the wire core applicator has a particularly dense bristle covering. In that case, it is basically clear that the separation capacity of such bristles can be increased further by producing the bristles from as hard a material as possible, which provides the bristle with a higher rigidity or buckling strength with the same diameter, and thus causes two positive effects:
A rigid bristle is inherently better capable of penetrating between overlying eyelashes of the curve of the eyelashes.
In addition, a rigid bristle has a much smaller tendency to evade the grinding disk, and therefore offers the possibility of a more pronounced grinding of the tips than a softer bristle.
However, the attempt to use hard materials and, in particular, hard plastic materials reveals the problem that the quality of the outer edge of the ground surface declines during grinding, i.e. that the edge no longer forms a clean continuous line, but often exhibits a ragged contour. This impedes the sliding of the eyelash along the edge and is therefore disadvantageous.
In view of this, it is the object of the invention to provide a wire core applicator covered with bristles that have a further improved separation capacity.